The present invention relates generally to a valve trains of an engine and more particularly to an interfacing between components of the valve train.
A typical four stroke compression engine includes a plurality of cylinders, a piston movably disposed within each cylinder, and a cylinder head. The valve train has a series of intake and exhaust valves positioned in the cylinder head, e.g. many engines have two intake and two exhaust valves per cylinder. As the pistons travel between a bottom dead center position and a top dead center position the valves are opened and closed by other valve train components allowing the engine to operate efficiently and effectively. More specifically, the operation of the valve train components require related components to transfer motion through an arcuate configuration and result in frictional contacting relationships. Such motion and configurations require pivotal joints and require an assembly of such pivotal joints to be substantially secured to prevent detachment of assembled components.
Within the valve train are a plurality of rocker arms, usually one rocker arm per valve or per a pair of valves. The rocker arms pivot about a shaft and are driven by push rods to open and close the valves during normal operation of the engine. In many present day engines each rocker arm has an insert therein having a button connected on the insert by an O-ring seal. The button engages a surface of a valve bridge to activate a pair of valves. The corresponding rocker arm pivots and the button pivots with respect to the valve bridge. Past experience has shown that the above described type of assembly is prone to premature failure due to grit from the engine being carried by the engine lubricating oil getting wedged between the O-ring seal and the insert or button. The grit eventually loges between the insert and the button and prevents the button from pivoting, fatigues and eventually causes the button to separate from the insert. The loose component can travel within the interior of the engine and cause premature failure of the engine
The present invention is directed to overcome one or more of the problems as set for the above.
In one aspect of the invention a rocker arm assembly has a rocker arm forming an insert bore. An insert is disposed within the insert bore and the insert including a hemispherical distal end. And, a button forms a hemispherical chamber which is sized and shaped to receive the hemispherical distal end of the insert. The button is press fitted onto the insert.
In another aspect of the invention a method for assembling a rocker arm assembly has the following steps. Providing an insert having a hemispherical end. Providing a button forming a hemispherical chamber that is sized and shaped to receive the hemispherical end. And, pressing the button onto the insert.